Bounded via the SOP-EDSL. minBound/maxBound are values, so this is pure injectSOP (no matchSOP): an enumeration injects its first/last (nullary) constructor; a single-constructor product injects that constructor with each field set to its own minBound/maxBound (pureFields + field). A clean demonstration that the SDK alone expresses a real synthesizer — this module needs nothing from the plugin substrate.